Certain medical conditions require that the heart be imaged for diagnostic purposes. Frequently, the patient's heart is imaged with a gamma camera. A gamma camera uses gamma rays to produce an image of the heart at a specific point in the heart cycle. For example, the physician might want to trigger the camera to image the heart on a P-wave, a T-wave or a QRS complex. In certain diseases, the T-wave can be large and present detectors may mistake a T-wave for a QRS complex. Thus, if the physician is looking for a QRS complex, the camera may be triggered twice: once on a QRS complex and once on the abnormal T-wave.
The radiation from the cameras is harmful in large doses. Therefore, the treating physician wants to ensure that the camera is only imaging at the desired point in the cardiac cycle, the QRS complex for example, to reduce the number of images taken.
The present invention addresses the problems associated with triggering a device based on a waveform in the cardiac cycle.